Electrical incandescent lamp.



go. 392,332. PATENTED JUNE so, woe.`

` o. M. THowLBss.

ELECTRICAL INCANDESGENT LAMP. APPLIoATIoN FILED 00126, 190e.

ORLANDO M. THOWLESS, OF NEWARK, NEW JERSEY.

.Specification of Letters Patent.

l ELECTRICAL INCANDESCENT LAMP.

Patented .rune ao, 196s.'

Application med 0mm 2s, loos. semi No. 340,723.

[o all whom it may concern:

Bc it known' that I, ORLANno M. Tnow- Lass, a subject of the King of Great Britain, riesiding at Newark, inthe county of Essex and State of' .New Jersey, have mvented a new and useful Improvement in Electrical Incandescent Lamps, of which the following is a specification.

The present invention relatest-o electrical incandescent lamps and more particularl to the class of lamps havin filamentary g o ers, and consist-s of a gglower, lacedin -a racuuni-lmlb and connected witli leading-in wires, formed of a tubeof metal of homo: gcneous, ductile and highly refractor lcharacter, having a fillinv of closelyac ed refractor metallic oxi material, w ich, when' pro erly packed, shall produce a body, capab e of being drawn and wrought into a filament, whiehlshall be pliable and of such,

ductility that it can bcdrawn around supports in the bulb without danfer of breakage,

in the same manner as though it were lnade of solid metal throughout, andthe object of. produce an electrical in this invention is to eandescent lamp withl a glower having the ualities of a dud'tile metallic filament, with t 1e added quality -of a higher electrical rcsistance for the same length and cross-section as a inet-allie filament would have if made of the same metal entirely. To attain this object I take a hollowcylinder of hi hly refractory metal, such as substantial y pure tantalum, or of anhalloy of substantially pure metals of the vanadium grou possessing ductility and having the quality of being ca able of manufacture into tubes, or of some ot'lier refractory ductile metals oralloys, or of so'me one or more metals of the )latinum g'roup, such as platinum, or an al oy of platinum with osmium, or with iridium, or with rhodium, or with ruthenium, or with any oral] of these, and in such eyliiuler I vpack a refractory substance, such as,thoria,

or nmgnesia, or celia, or zirconia, or vttria, or

, The matelial selected for the filling .should be in a fine powder, and must be tightly packed in the metal cylinder, and any air, moisture or occluded ases should be, as much as possible, driven rom the fillinrr material, or a rupture of the walls o f the gllower might be caused durin theo eration of drawin down. The cylint er, w en properly pac ed, is then treated as though made of solid metal in the lamp is ready for use.

. carbon cominr -when it is heated.

manner employed in .drawing wire.- It will be found when the wire, as it may be termed, is vdrawn or worked, the result will vbe a tubular shell of metal containing, all through the interior, a uniform, closely-packed, cpntinuous core of non-conductive refractory material, `the finished wire fectly pliable and ready for cutting into with the core being perlengths. .Each length can then be laced in 'a lamp bulb; connected with lea in .-in

wires, by means of cement or solder, or astened or attached to them in ,any proper way; sealed and thebulbs 'exhausted an'd finished in the old and well-known manner, and the The" bulb may con'- tain indifferent gases instead of being exhausted. r

While, for ordinary ur oses, the filamentar y form of glowing'bodp may be used, a rodyor. rods may, for hig er candle- Jower, be requisite, 'as such rods will be foun to be quite economical, for only the metallic part will take current if. proper refractory material is used for the core.

VVh'en'v the filament is finished the result will be an incandescing body for electrical glow-lamps formed of a conducting metallic exterior containing a continuous ductile core, non-conductive at all temperatures at which the filament is operated therefore the metallic part only will take current so that the resistance-for a given lengthand cross-section will be enormously raised uscom )are-d with a filament'made of solidl metal having the same dimensions. This is of the highest. importance as filaments, made of solid refractor metals, are of such low resistance that it 1s found necessary to make them of so' great a length as to limit the use of 'filaments made of tantalum, niobium, molybdenum, tungsten, vanadium, osmium, ruthenium and others, while with my invention metals of ductility may be used of shorter lengths. for the same resistance. ln making the filaments great care must be taken in the annealing to revent any in contact with t ie metal, as al carbid miglit be formed with the metal In some 'instances it may be desirable to use metals of the platinum group, but only those havingthe quality of ductility will be of service. Also alloys of the platinum group may be used in somecases, such as platinum and iridium, platinum and ruthenium, or rhodium, or osmium,

or palladium, or any of these which would form ductile refractory alloys, or single metals may be used of the above, if ducti e.

The words non-conducting.' and nonconductive used in this specification are to. be understood as expressing that the materials mentioned as non-conductive or non-conductingf are in a non-conducting electricall condition when cold and at a temperatures at which the filaments are operated.

In the accompanyin drawings, Figure 1 is a view of an e ectric am illustrating my invention. Fi 2 is an en arged view of a portion of the lament of the lamp aart of which is shown broken away to (lisp ay its construction.

Similar letters refertosimilarl parts in both figures, in which A, is 4the lamp-bulb, B, the g Biss stem in which the leadingn wires arq sealed; C,- shows the cement or oint between the Wireslan'd: the filament; represents? theiilamentI generally, E .is the metallic; tubular shell part; F, the filling or core part; G r resents supports for the iilament; whil full, shows the leading-in wires'.

In 'v '2`thc more particular cons tiuction of the ilament' isyshown by E, the tubular shell; and F, the filling, while in 1 the letter D re resents the filament as awhole.-

Having t ius described my invention, 'what I claim is:

L'n im candescent amps, comprisina refractory non-conductive core having t ereon aconsubstantially pure tantalum filled-through# roved glower for electrical tinuous coatingof homogeneousrefractoiy l out its interior with a compactcore of refractory non-conductive metallic oxid.

candescent amps, com osed of a thin tube Yof ductile metallic tanta um containing a core of refractory non-conductive substance.

4. An im roved glower for electrical incandescent amps, having a high resistance as compared with solid metal, consisting of a tube of substantially pure tantaliiin coutaining a full and closely-united corc of rcractory non-conductive material.

5. An im roved glower for electrical incandescent amps composed of a thin shell of ductile metallic tantalum containinga core formed of refractory non-conductive substance.

6. An improved glower for electrical inof wrought metal of the vanadium group and i containing therein a core of refractory nong'conductive metallic oxid.

7. An im roved glowr for electrical iucandescent ampsv consisting of a wrn lit filament formed of a shell ofo'ductile metiilic tantalum containing a liable core of refrac-- tory non-conductive su stance.-

8l An improved glower for electrical incandescent lamps, composed of a ductile refractory metallic tube containing a compact pliable core of two subscribing witnesses.

. ORLANDOMTHOWLESS.

' ARTHUR J. T nowucss. i

3. An im roved glower for electrical in-` cantlescentlanips consisting of a shell formed f refractory non-conductive metal- In testimony lwhereof, I have signed my name to this specification, in the presence of l i 

